In a known manner, said machines include an infusion unit providing the extraction of a product such as coffee. An infusion unit usually comprises an extraction chamber that is sealed during the extraction phase and capable of being opened to receive or release the product that is being used for the infusion. The outlet of the chamber leads into a container such as a cup.
One of the most common infusion systems uses an extraction chamber produced in two portions, one being fixed and the other rendered mobile. One of the two half-chambers comprises the pressurised hot water inlet whereas the other has a spout through which is distributed the infused coffee from the dose contained in the extraction chamber. The infusion pressure being provided by a pump embedded in the machine, it is possible to use the hydraulic pressure of said same pump to provide the movement of the mobile half-chamber by associating thereto a hydraulic cylinder in order to provide the automatic closing thereof limiting the human effort. Such a machine is known for example from document WO-A-20081142040.
In numerous machines, the unit is fixed onto the frame of the machine in a non-removable manner. The dismounting thereof is therefore rendered very difficult or even impossible. This is particularly disadvantageous for the cleaning thereof, the maintenance thereof or the end-of-life recycling thereof, by not meeting the eco-design requirements which impose the dismantling and the recycling of component parts of such machines.
Moreover and especially, as expresso coffee is produced by infusing a predetermined amount of roasted and ground coffee with hot water at very high pressure through a previously sealed extraction chamber, the higher the infusion pressure the greater the closing force of the two half-chambers must be significant to provide the sealing during the infusion.
The significant force applied to the fixed half-chamber and resulting from the pressure of the driving means of the mobile half-chamber causes in reaction a force just as significant but in the opposite direction on said driving means. Said two opposite forces must imperatively be withstood by a correctly dimensioned mechanical element to prevent the destruction at least partial of the machine.
Given the significant pressure involved in domestic expresso machines, up to 20 bars, the mechanical element clasping the driving means for the mobile chamber, said driving means frequently being in the form of a cylinder, as well as the two infusion half-chambers, and withstanding the resulting forces is currently produced from the complex assembly of a plurality of large section metal elements, generally made of steel. Said various elements are subject to corrosion, being more voluminous and heavy which results in a significant minimum volume for the entire machine, to the detriment of the economic cost thereof as well as the environmental impact thereof for both the use of natural resources and the amount of energy required for the manufacturing thereof and distribution thereof.
Thus, there is a need to design a pressure-resistant infusion unit whilst being less voluminous and less heavy than the units proposed in prior art.
There is also a second need to design an installation of at least one element to be inserted into the unit that is easy to achieve, said element may be, for example, the fixed and/or mobile half-chamber or chambers as well as the driving means of the mobile half-chamber and also auxiliary devices for guiding the dose or sequential closing and/or opening of the half-chambers.
The present invention aims to meet at least one of said needs.